ANGULAR DEFLECTION

When a pipe expansion joint
experiences bending about its center, which is on the centerline
and halfway between the ends of the bellows, this deflection is
referred to as ANGULAR. It can occur in any plane that passes
through the centerline, but the plane should be clearly indicated
if the pipe expansion joint is more complicated than the simplest
type, i.e., only a bellows with flanges or pipe ends. As in
lateral movements, piping analyses may reveal angular deflections
occurring in more than one plane. With ANGULAR DEFLECTION, the
basis for the proper selection is the maximum of the various
deflections, and not the vector sum as in the lateral case.
Multiple ANGULAR DEFLECTIONS in multiple planes produce a single
ANGULAR DEFLECTION in a single resultant plane. As in lateral
deflection, this plane must be understood if structural
components are to be used.